A new study shows that older women with sleep-disordered breathing, a condition that causes frequent sleep disruptions and drops in oxygen levels, were more likely to develop memory problems or dementia than those without the sleep disorder.

Researchers say sleep-disordered breathing is common among older adults and affects up to 60% of the elderly. The disorder has also been linked to an increased risk of high blood pressure, heart disease, and diabetes.

Although previous studies have linked sleep-disordered breathing to memory problems and dementia, researchers say it is unclear whether the sleep disorder plays a major role in the development of these age-related conditions.

Sleep Breathing Tied to Memory

In this study, researchers compared the risk of memory problems and dementia in a group of 298 women with an average age of 82 who were evaluated for sleep-disordered breathing between 2002 and 2004 and then tested for memory status nearly five years later.

By the end of the study, 36% of the women had developed mild memory problems (20%) or dementia (16%).

The results showed that 45% of women who had sleep-disordered breathing developed memory problems or dementia, compared with 31% of those without the sleep disorder.

Researchers found decreased oxygen levels caused by sleep-disordered breathing were linked to a higher risk of mild memory problems or dementia. In contrast, the number of sleep disruptions or total sleep time was not associated with this risk.

The results suggest that lower than normal oxygen levels in the blood associated with sleep-disordered breathing may contribute to memory problems in the elderly.

“Given the high prevalence of both sleep-disordered breathing and [memory problems and dementia] among older adults, the possibility of an association between the two conditions, even a modest one, has the potential for a large public health impact,” write researcher Kristine Yaffe, MD, of the University of California, San Francisco, and colleagues in the Journal of the American Medical Association.

“This is especially important because effective treatments for sleep-disordered breathing exist,” they write.